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Background: Campylobacter is the most common food-borne pathogen in the European Union. In 2018, the crude incidence rate in Ireland was 63.6 per 100,000 population. Chicken is considered an important source of infection for humans. In 2015, the Campylobacter Stakeholders' Group (CSG) was established to reduce Campylobacter contamination levels in Irish broiler flocks., Aims: This work aimed to describe the Campylobacter monitoring programme that was established by the CSG, to analyse the results of this testing between 2019 and 2022, and to assess progress., Methods and Results: This paper describes the monitoring programme that was established by the CSG, which harmonized Campylobacter enumeration testing across all Irish broiler processors and allowed comparability of results for trend analysis. An analysis of the 2019-2022 data is presented here and compared to previous studies of Campylobacter levels in Irish broilers. An analysis of the 2019-2022 data showed a significant reduction in levels in both caeca and neck skin when the results from 2022 were compared to those from 2019 to 2020. Campylobacter spp. were detected in 37% of caecal samples from first depopulation (pre-thin) broilers and 30% of neck skin samples in 2022, with just 4% of carcases (in neck skin samples) with ≥1000 colony-forming units per gram detected in 2022. Campylobacter levels detected in Irish broilers, in the present monitoring programme were less than those reported in previous studies in both caecal and carcase samples, although not directly comparable for statistical significance because of differences in study methods., Conclusions: The cooperation between stakeholders and regulators of the Irish broiler chicken industry over the past decade has facilitated a coordinated approach to monitoring of Campylobacter levels in broilers, and implementation of control measures. This has enabled a steady reduction in the levels of Campylobacter in Irish chicken., (© 2024 Wiley‐VCH GmbH.)

Osteoarthritis is the most common degenerative joint condition, leading to articular cartilage (AC) degradation, chronic pain and immobility. The lack of appropriate therapies that provide tissue restoration combined with the limited lifespan of joint-replacement implants indicate the need for alternative AC regeneration strategies. Differentiation of human pluripotent stem cells (hPSCs) into AC progenitors may provide a long-term regenerative solution but is still limited due to the continued reliance upon growth factors to recapitulate developmental signalling processes. Recently, TTNPB, a small molecule activator of retinoic acid receptors (RARs), has been shown to be sufficient to guide mesodermal specification and early chondrogenesis of hPSCs. Here, we modified our previous differentiation protocol, by supplementing cells with TTNPB and administering BMP2 at specific times to enhance early development (referred to as the RAPID-E protocol). Transcriptomic analyses indicated that activation of RAR signalling significantly upregulated genes related to limb and embryonic skeletal development in the early stages of the protocol and upregulated genes related to AC development in later stages. Chondroprogenitors obtained from RAPID-E could generate cartilaginous pellets that expressed AC-related matrix proteins such as Lubricin, Aggrecan, and Collagen II, but additionally expressed Collagen X, indicative of hypertrophy. This protocol could lay the foundations for cell therapy strategies for osteoarthritis and improve the understanding of AC development in humans., (© 2024. Crown.)

Optogenetics is a rapidly advancing technology combining photochemical, optical, and synthetic biology to control cellular behavior. Together, sensitive light-responsive optogenetic tools and human pluripotent stem cell differentiation models have the potential to fine-tune differentiation and unpick the processes by which cell specification and tissue patterning are controlled by morphogens. We used an optogenetic bone morphogenetic protein (BMP) signaling system (optoBMP) to drive chondrogenic differentiation of human embryonic stem cells (hESCs). We engineered light-sensitive hESCs through CRISPR-Cas9-mediated integration of the optoBMP system into the AAVS1 locus. The activation of optoBMP with blue light, in lieu of BMP growth factors, resulted in the activation of BMP signaling mechanisms and upregulation of a chondrogenic phenotype, with significant transcriptional differences compared to cells in the dark. Furthermore, cells differentiated with light could form chondrogenic pellets consisting of a hyaline-like cartilaginous matrix. Our findings indicate the applicability of optogenetics for understanding human development and tissue engineering., Competing Interests: Declaration of interests The authors declare no competing interests., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Developmentally, the articular joints are derived from lateral plate (LP) mesoderm. However, no study has produced both LP derived prechondrocytes and preosteoblasts from human pluripotent stem cells (hPSC) through a common progenitor in a chemically defined manner. Differentiation of hPSCs through the authentic route, via an LP-osteochondral progenitor (OCP), may aid understanding of human cartilage development and the generation of effective cell therapies for osteoarthritis. We refined our existing chondrogenic protocol, incorporating knowledge from development and other studies to produce a LP-OCP from which prechondrocyte- and preosteoblast-like cells can be generated. Results show the formation of an OCP, which can be further driven to prechondrocytes and preosteoblasts. Prechondrocytes cultured in pellets produced cartilage like matrix with lacunae and superficial flattened cells expressing lubricin. Additionally, preosteoblasts were able to generate a mineralised structure. This protocol can therefore be used to investigate further cartilage development and in the development of joint cartilage for potential treatments., Competing Interests: No, there is no conflict of interest. My manuscript contains the following statement: "The authors declare that they have no conflict of interest.", (Copyright: © 2023 Smith et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)